When it comes to initial signs of in-flight fire and smoke, the more pilots know and the sooner they know it, the better, experts on the subject tell Air Safety Week. But one thing that could help is a new smoke/fumes/fire (SFF) checklist that groups like the Air Line Pilots Association, International (ALPA) are pushing the aircraft manufacturers to adopt.
From the pilots’ standpoint, there’s an immediate need to know the nature and the intensity of fire, including exactly where it is and how big it’s gotten already, says current commercial airline pilot, Captain H.G. “Boomer” Bombardi, ALPA’s in-flight fire project team leader.
But the problem with most fires is that it’s very difficult to tell where they’re coming from, he explains. A flight attendant might report smoke coming from the floor in the aft galley, which could be from a nearby fire, or could be coming from the middle of the craft and is being carried back to the rear. It’s also hard to tell if smoke is only coming from a little bit of burning insulation, or there’s a fairly serious fire that’s about to go through some control cable.
Bombardi first became involved with SFF issues in the U.S. Air Force, where he helped rewrite SFF procedures for the C-141, ALPA says. Since 1987, he’s been a pilot for Delta Air Lines, where he’s also helped revise SFF procedures.
There are fairly helpful checklists for pilots to troubleshoot just about everything on the aircraft — everything that is, except fire and smoke, Bombardi adds. Generally speaking, pilots are forced into making life-or-death decisions with little information. Different airlines also have varying procedures.
This is why ALPA and some others, including the International Air Transport Association (IATA) and Bombardier, started discussions last year to develop a new SFF checklist, which is intended for general adoption across different airlines, with room for the specifics of individual craft. The Flight Safety Foundation eventually came in and coordinated the effort, because none of the other partners wanted to be the one making changes, Bombardi says. The new checklist places an emphasis on landing the plane as soon as possible, especially if the nature of the smoke or fire can’t be quickly determined.
Under the traditional philosophy in the cockpit of responding to in-flight fires, he continues, there’s been a “we can figure out what the problem is” attitude predominating. If pilots suspect the fire started in the electrical system, then they start going through the checklist for electrical fires. For another suspected cause, there’s another checklist. The problem with this approach is, of course, if the initial assumption is not correct, then minutes of precious time are wasted.
In contrast, the new checklist starts with trying to determine the origin of the fire. It also would be more aircraft specific, taking into account whether that particular model has had more than its share of problems, for example, with re-circulation fans. Then one of the early items on the checklist would tell pilots to shut the fans off.
Moreover, as procedural and technological improvements continue to decrease the risk of in-flight fires, Bombardi asserts that he’ll still be “stuck with the reality that there’s going to be fires on the aircraft.”
Similar ideas are also stressed by aviation safety consultant, Captain John Cox. Even as the FAA now recognizes, it’s just not possible to design out of aircraft all the potential for starting and propagating in-flight fires. So, the best tack is to pursue a variety of promising mitigation techniques, like improving the development of redundant systems, giving crews the earliest possible indication that a fire may exist, and revising response procedures and maintenance schedules.
Cox, who is president of Safety Operating Systems, LLC, also has been on the road lately giving presentations on his new paper, “Reducing the Risk of Smoke and Fire in Transport Airplanes: Past History, Current Risk and Recommended Mitigations.”
One of the most interesting accidents that he came across after 18 months of reviewing the accident records was the May 16, 1995, crash of a British Aerospace (BA) Nimrod R.1P (operated by the Royal Air Force) into the Atlantic Ocean, in which all seven aboard survived. Cox found that a wiring problem sent a spurious command to a starter valve to open. With the engine already operating, the starter valve then began to “overspeed massively,” which it was not designed to do. As it result, it shattered and came out of its housing, puncturing a fuel cell and causing a very damaging in-flight fire. What was particularly interesting, Cox tells Air Safety Week, is how the initial small malfunction defeated all the redundancy built into the aircraft.
That lesser known accident is reminiscent of the September 1998 crash of Swissair 111, “which really showed the complexity of what fire can do,” Cox says. As fire spread from one wiring bundle to another, it quickly started taking down a number of unrelated systems.
In his report, Cox makes a number of recommendations in areas that are probably familiar to pilots and others in the aviation community, regarding such cascading system failures and ways for revising personnel training, among other things. Air Safety Week also asked Cox to point out a couple of highlights.
One action that would nip some incipient fires in the bud would equip every aircraft with an arc fault circuit interrupter, which are available from a number of manufacturers, including BA, Boeing, and Texas Instruments, Cox says. These devices work by detecting an electrical arcing event, then by turning the current off on that particular circuit. They’re more reliable than circuit breakers that rely on thermal readings. Furthermore, testing has shown that they are not prone to “nuisance activation.”
Another recommendation involves the aircraft certification testing the FAA requires for testing continuous smoke conditions in the cabin and cockpit. For some reason, the circular instructs the smoke generator to be turned off and the cockpit ventilated after only three minutes. This does not exactly simulate real-world conditions. For testing for all other sections of the airplane, the agency requires continuously generated smoke. Cox adds that there is no apparent reason for the disparity.
Another interesting observation is that, in many cases, cabin crews inform the pilots of a smoke problem by opening the cockpit door. “But that’s the last thing they need to do,” Cox says. The cockpit door is an integral part of the craft’s fire mitigation system.
Other needed regulatory revisions would ensure that pilots can adequately see what they’re doing and ensure that all members of the flight crew quickly have access to oxygen. Beyond the procedures for decompression events, access to oxygen is not addressed.
At FAA’s William J Hughes Technical Center, Dick Hill, program manager for aircraft cabin and fire safety, tells Air Safety Week that the center takes a twofold approach to fire and smoke mitigation. One is to make sure the fire ignition sources are cut off, and the second is raising the flammability standards of materials installed on aircraft. The latter is the subject of a major new rulemaking that the FAA is working to finalize (Air Safety Week, March 6).
>>Contacts: Captain H.G. “Boomer” Bomardi, ALPA, (703) 689-4342; Captain John Cox, (202) 575-6100, [email protected]<<